This invention relates generally to pressure-actuated switches, and, more particularly, to pressure-actuated switches of the adjustable type, i.e., adjustable to complete an electrical circuit in response to a selected threshold pressure. Such switches have a wide variety of applications, and are particularly useful in the field of respirators, the operation of which depends on the accurate and repeatable sensing of pressure.
Although there are many pressure-actuated switches of the adjustable type, most of them have no convenient means for calibration. Furthermore, even switches having a calibration means are typically so unreliable as to necessitate recalibration each time an adjustment is made to the threshold pressure setting. It will be appreciated, therefore, that there has long been a need for a pressure-actuated switch of the adjustable type which can be conveniently calibrated, and which requires no recalibration after each adjustment. The present application is directed to this end.